Hi both and welcome to Eribafolk.

The 320 is a lovely size Eriba and is quite easily towed by most family sized cars. Personally I think you're correct to go for an estate car as the car can share the carrying capacity of the Eriba. For example, we've towed our Eriba with a VW Touran for nearly ten years now and before that it was a 1.6 Focus Estate TDi and are able to carry loads of extra junk in the car.

If you're not too concerned with matching the smallest car possible then any of the cars you mention will fit the bill and should tow the 320 easily with that little bit of extra performance in reserve if you need it to get you out of trouble.

Randa

Welcome and congratulations.
With your Famila you should find that any modern 1.6/2.0L diesel will do the job without problem, regarding weight and power. You would also expect to see mid 30's mpg.
An estate or hatchback would be a good choice, or if you like the height an mpv/crossover. Best thing is look on the https://towcar.info/GB/ website. Remmber to increase weights for car and van payload to get real life results. 400kg and 300kg would be sensible amounts.
It is always better to go a bit bigger than you think you need but consider what % of your driving is with the van during the year. Remember you might also get the next size up van a few years down the line and do not want to be in the situation where you need to upgrade the car.
Like Randa I ran a 2.0L diesel Touran for 10 years. It was probably the best family car we have owned. It was HUGE inside as you could take the back seats out but only a little longer than a Golf. I replaced it with a diesel Yeti, probably the best car we have owned and ran this for 5 years.
I recently went outside the box and bought a petrol 1.5 Audi A3 as I was told the polar bears are dieing and I was not allowed another diesel. What has turned out to be a revelation is how good modern petrol engines are. The Audi is a dram to drive, towing our Triton far more comfortably than either the Touran or the Yeti. The boot is also bigger than the Yeti's. Your search may not be as simple as you think so keep an open mind.
If I was allowed to have gone the diesel route then a Mazda CX5 would have been at the very top of my list.

Colin